Methods and devices for diastolic assist

ABSTRACT

The devices and method described herein allow for therapeutic damage to increase volume in these hyperdynamic hearts to allow improved physiology and ventricular filling and to reduce diastolic filling pressure by making the ventricle less stiff.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/085,509 filed Mar. 30, 2016, which is a continuation of InternationalApplication No. PCT/US2014/058438 filed Sep. 30, 2014, which claims thebenefit of priority to U.S. Provisional Patent Application Nos.61/884,332 filed Sep. 30, 2013, 61/911,456 filed Dec. 3, 2013, and62/046,863 filed Sep. 5, 2014. PCT/US2014/058438 filed Sep. 30, 2014 isalso a continuation-in-part of U.S. patent application Ser. No.14/152,189 filed Jan. 10, 2014, the contents of which are incorporatedherein by reference in their entireties

BACKGROUND OF THE INVENTION

Congestive heart failure (CHF) in the United States has a prevalence ofapproximately 5.8 million people and an incidence of approximately550,000 people annually. CHF is a rapidly growing medical problem. CHFcan be categorized as either systolic heart failure (SHF) or diastolicheart failure (DHF). The estimated direct and indirect cost of CHF inthe United States for 2009 is $37.2 billion. CHF is the primary reasonfor 12-15 million office visits and 6.5 million hospital days each year.CHF is also thought to be the cause of at least 20 percent of allhospital admissions among patients older than 65. Over the past decade,the rate of hospitalizations for heart failure has increased by 159percent. About half of all patients with CHF have DHF. DHF has an annualmortality of ˜10%.

The hearts of patients with diastolic dysfunction can contract normallyor even with hyperdynamic function. However, in patients experiencingDHF, the part of the cardiac cycle that involves diastole is abnormal asthe left ventricle cannot relax or expand sufficiently. The inability ofthe left ventricle to fully relax results in sub-optimal filling of theleft ventricle with blood.

In particular, diastolic dysfunction is determined by two factors: 1)active myocardial relaxation, primarily affecting early diastole; or 2)passive elasticity or distensibility of the left ventricle, primarilyaffecting late diastole.

The abnormal filling of the ventricles in DHF results in limited cardiacoutput, especially during exertion. As a result, for any givenventricular volume in a heart with DHF, ventricular pressures areelevated, with backup in the circulatory system, leading to pulmonarycongestion and edema identical to those seen in patients with SHF.Symptomatically, patients may immediately feel short of breath. Thisdysfunction can ultimately lead to multiorgan dysfunction and death.

There are currently no approved devices for diastolic dysfunction.Additionally, pharmaceutical intervention has not yet shown to improveoutcomes in this population.

BRIEF SUMMARY OF THE INVENTION

The present disclosure includes devices and methods to increase volumein these hyperdynamic hearts to allow improved physiology andventricular filling and to reduce diastolic filling pressure. Forexample, the treatments described herein, when performed in a diseasedheart, can result in the heart chamber filling to an increased volume ofblood (as compared to pre-treatment volumes) at the same pressure.Thereby, the chamber can move more volume than it could pre-treatment.

In a first variation, the disclosure includes a method of improving adiastolic heart function in a heart of a patient having diastolic heartdysfunction. One variation of the method includes positioning a medicaldevice within a body of the patient; advancing the medical device intoan interior chamber of the heart; creating at least one incision incardiac muscle forming an interior heart wall of the interior chamberwithout cutting through the exterior part of said heart wall, where theincision is sufficient to reduce a stiffness of the interior chamber toincrease volume of the chamber and reduce diastolic filing pressure.

The above method can further include creating a plurality of incision.The plurality of incision can comprise at least one hole in the cardiacmuscle or can comprise creating a plurality of incision.

Typically the method includes creating at least one incision withoutreducing the integrity of the cardiac muscle.

Access to the heart can occur via a vascular approach, an open surgicalapproach, or a thoracoscopic approach. Furthermore, advancing themedical device can comprise advancing the medical device into theinterior chamber of the heart via a transapical approach.

The devices used to create the therapeutic injury can include anydevices selected from the group consisting of a blade, a mechanicalcutting device, an electrosurgical device, and a laser device.

In some variations, the methods occur by inducing tachycardia of theheart. Furthermore, incisions can be created on an interior of theheart.

The devices can be secured to cardiac muscle prior to or during creatingthe incision.

The methods and devices can also optionally deliver bioactive agent toat least one incision to modify the healing process of the cardiacmuscle.

Another variation of the method includes a method of increasing bloodflow in a diseased heart. One such example includes positioning amedical device within a body of the patient; advancing the medicaldevice into an interior chamber of the heart; locating a target area ofheart tissue; and creating at least one incision in cardiac muscle ofthe heart tissue to decrease the stiffness of the interior chamber topermit the interior chamber to increase in volume during diastole. Onevariation of the device used to make the one or more incisions mentionedabove includes a soft semicircular tip at the distal end of the devicethat may be in fluid communication with an injection port outside thepatient. The tip can be imaged when inside the heart under xrayfluoroscopic imaging or any other type of imaging or virtual tracking.When the tip is placed into the area of the apex of the heart, the tipconfiguration changes and the change can be seen during imaging. Acontrast imaging agent may be injected through the tip when injectedoutside the patient through the injection port. Said contrast agentflows into the ventricle. The pattern of flow gives information to theuser as to where the cutting member is relative to the inside wall ofthe ventricle. When the cutting member is adjacent to or embedded in themuscle of the heart wall, the contrast agent will flow only to thesurface of the inside wall while the cutting element will be seen withinthat wall. The contrast agent can also be seen within the cut made inthe heart wall.

Another variation of the methods includes methods of increasing bloodflow in a diseased heart by advancing a device within a left ventricleof the heart; placing an elastic member within the left ventricle suchthat upon diastole the elastic member expands with the left ventricle.The elastic member has one or more arms. At least one of these arms mayhave a cutting member. The cutting member may be moved along the insideof the ventricle wall making a controlled incision therein. The depth ofthe incision is controlled by the distance between the arm and/orelastic member and the tip of the cutting member. If several cuttingmembers are included, these members may be moved individually ortogether by a cable or other coupled member connecting the cuttingmember to an actuator outside of the patient. to increase a volumewithin the left ventricle so as to increase blood flow therein.

The elastic member can comprise a plurality of elastic memberspositioned in a substantially concentric pattern within the leftventricle. Alternatively, or in combination, the elastic member cancomprise at least one spirally shaped elastic member positioned in asubstantially concentric pattern within the left ventricle.

The present disclosure also includes variations of medical devices forcreating the elongated incisions within soft tissue. In one example thedevice comprises a handle comprising a handle body and an actuatingmember; a flexible shaft having a near end coupled to the handle bodyand a far end, the flexible shaft; an atraumatic tip located at the farend; a cutting member pivotally secured within the flexible shaft andhaving a cutting edge; and a linking member coupling the actuatingmember of the handle to the cutting member, wherein when the actuatingmember applies a tensile force to the linking member, the cutting memberpivots to a lateral side of the flexible shaft to expose the cuttingsurface and allow cutting of the soft tissue, the tensile force alsocausing biasing of the far end of flexible shaft towards the lateralside to assist in maintaining the cutting surface within the softtissue. Alternatively, the device may be introduced into the heartthrough a guiding catheter. Such guiding catheter can be flexible anddirected from outside of the patient and can be either flexed activelyby the user or can be preconfigured in one or more shapes. Severalshaped guiding catheters can be included in a kit to perform theprocedure. Alternatively, or in combination, such catheters can beactuatable upon command or upon reaching a certain condition (e.g., bodytemperature, use of a stylet, etc.)

A variation of the device includes a channel extending between the nearend of the flexible shaft through the opening. In addition, the medicaldevice can further include a sheath being slidably located on theflexible shaft, where the sheath can be advanced to cover the openingand retracted to expose the opening.

Variations of the medical device can include a cutting member thatcomprises an electrically non-conductive material. In such cases, thecutting member can optionally include at least one electrode located onthe electrically non-conductive material, where the at least oneelectrode is electrically coupleable to a source of electrical current.

In alternate variations, the cutting member comprises an electricallyconductive material and where the cutting member is electricallycoupleable to a source of electrical current.

The devices described herein can have one or more openings adjacent tothe far end of the flexible shaft, where the cutting surface of thecutting member extends through the opening when pivoted. In somevariations, the device further comprises one or more electrodes adjacentto the opening.

The devices described herein can further include a rigid section at thefar end of the flexible shaft where the rigid section comprises anopening through which the cutting surface of the cutting member extendswhen pivoted. As discussed herein, the rigid section at the far end ofthe device provides uniformity to create the incision, while theflexible nature of the shaft permits navigation to remote tissuesthrough tortuous anatomy.

The devices described herein can include an atraumatic tip located atthe far end of the flexible shaft. The atraumatic tip can comprise acurved elastic member or any shape that provides a lateral force toassist the cutting member to penetrate tissue. Alternatively, theatraumatic tip can simply comprise a blunt elastic or inelasticmaterial. Variations of the devices can include atraumatic tips that areradiopaque.

Furthermore, the devices described herein can employ any additionalnumber of lumens for fluid delivery, guidewire advancement, imaging,etc.

This application is related to U.S. Publication No. 2012/0296153 U.S.patent application Ser. No. 13/277,158 filed on Oct. 19, 2011; U.S.application Ser. No. 14/152,187 filed on Jan. 10, 2014and U.S.Provisional Application Nos. 61/394,759 filed on Oct. 19, 2010;61/478,495 filed on Apr. 23, 2011; 61/504,641 filed on Jul. 5, 2011;61/884,332 filed on Sep. 30, 2013; and 61/911,456 filed on Dec. 12,2013, the contents of which are each incorporated herein by reference inits entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A and 1B, illustrate respective top and side views of a firstexample of a treatment device that can be used to make incisions in softtissue according to the present disclosure.

FIG. 2A illustrates perspective partial cross sectional view of a farend of the device of FIGS. 1A and 1B.

FIG. 2B illustrates a partial side view of the device above showing thelink being secured between the actuating member and cutting member.

FIG. 2C illustrates a proximal or tensile force applied to the linkcausing the cutting member to pivot out of the opening towards a lateralside of the device.

FIG. 3A illustrates a variation of the device where a rigid section ofthe flexible shaft comprises an enclosure that is secured to a distalend of the flexible shaft.

FIG. 3B shows a variation where the flexible shaft houses the cuttingmember with a reinforcement member (either external or internal to theshaft) coupled to the flexible shaft where the reinforcement memberrenders the area as a rigid section.

FIGS. 4A to 4C illustrate advancement of a device into a heart to createa lesion as described herein.

FIGS. 5A to 5C illustrate additional variations of the device whereapplication of a lateral force can be separated from actuation of thecutting member.

DETAILED DESCRIPTION OF THE INVENTION

The illustrations described herein are examples of the invention.Because of the scope of the invention, it is specifically contemplatedthat combinations of aspects of specific embodiments or combinations ofthe specific embodiments themselves are within the scope of thisdisclosure.

As noted above, the methods described herein increase a volume of achamber of a heart to improve blood flow in diastolic heart failure. Forexample, incisions, cuts, holes, or other separation of tissue can bemade in muscle forming the wall of the left ventricle to improve adiastolic function of the heart. Although the description and claimsdescribed herein discuss primarily treatments occurring in a leftventricle, unless specifically discussed or claimed, the treatments canoccur in any chamber of the heart (e.g., the atriums and/or ventricles).Typically, access to the chambers of the heart (endocardium) can be madepercutaneously or via a transapical approach. Once in the ventricle,small cuts, holes, or a combination thereof are made to the cardiacmuscle at one or more layers of the musculature.

One of the goals of the therapeutic damage is to increase volume inthese hyperdynamic hearts to allow improved physiology and ventricularfilling and to reduce diastolic filling pressure by making the ventricleless stiff. In some cases, the type of therapeutic damage, e.g., angles,dimensions, length, depth, density, and architecture shall balance ofthe integrity of the musculature versus the functional result. Meaningthe amount of therapeutic damage to the tissue must be balanced againstcompromising the integrity of the tissue. In many cases, the treatmentcan be optimized to ensure adequate function physiologically,hemodynamically, and electrophysiologically. Unless otherwise specified,the therapeutic treatments only extend into one or more layers of thecardiac muscle and not through the wall of the heart.

The therapeutic damage caused to the cardiac muscle can be additionallytreated with agents that prevent closure of the wounds. Such agents caninclude pyrolitic carbon, titanium-nitride-oxide, taxanes, fibrinogen,collagen, thrombin, phosphorylcholine, heparin, rapamycin, radioactive188Re and 32P, silver nitrate, dactinomycin, sirolimus, everolimus,Abt-578, tacrolimus, camptothecin, etoposide, vincristine, mitomycin,fluorouracil, or cell adhesion peptides. Taxanes include, for example,paclitaxel, 10-deacetyltaxol, 7-epi-10-deacetyltaxol,7-xylosyl-10-deacetyltaxol, 7-epi-taxol, cephalomannine, baccatin III,baccatin V, 10-deacetylbaccatin III, 7-epi-10-deacetylbaccatin III,docetaxel. Other agents that could effect improved function includebioactive substances including proteins and cells like stem cells.

FIGS. 1A and 1B, illustrate respective top and side views of a firstexample of a treatment device 100 that can be used to make incisions insoft tissue according to the present disclosure. As shown, the deviceincludes a handle 102 comprising a handle body 104 and an actuatingmember 106. Variations of the device can include handles of any numberof configurations. Typically, such variations include an actuatingmember that is moveable relative to a handle body. Such examples caninclude triggers, levers, dials, etc. Furthermore, the actuating portioncan include a switch type mechanism in the event the respectivevariation is driven by a motor or other automated means.

The device 100 further includes a flexible shaft 110 that extendsbetween a near end 112 and a far end 114. In the illustrated example,the near end 112 depicted as having an optional stress relief sleeve aswell as a fluid port 116 for administering fluid through the device 100.The devices can also include an optional source of current for couplingto electrodes on the device 100 (as described below), for pacing thesoft tissue, monitoring EKG, determining whether the device's cuttingmember is embedded within tissue, electrocautery, coagulation and/orelectrodeposition of medicines or other substances. Similarly, thedevice 100 can include one or more sources of fluid 134 for coupling tothe device 100 via a fluid port 116. The fluid can be dispensed throughthe cutting member opening 124 or through a separate opening.

Variation of the device 100 can also include an atraumatic tip 120 thatcan optionally be selected to be radiopaque. Alternatively, or incombination cutting element can be radio-dense so it is visible and itsposition can be determined during use. The example depicted in FIGS. Aand 1B includes an atraumatic tip having the shape of a curved elasticmember. In those cases where the device 100 is used in the heart orother cavity the atraumatic curved member 120 protects the tissue frombeing punctured by the tip of the device 120. The elastic curved member120 can also flex and relax when pushed into the apex of the heart orcavity. In those variations where the flexed tip 120 is radiopaque, aphysician performing the procedure will be able to observe the shapechange of the tip under fluoroscopic imaging. When physician thenactuates the device to cut tissue, the elastic property of the tip 120pushes far end 114 of the device against tissue and assists in keepingthe cutting element or member within the soft tissue while the cut isbeing made. Such a feature is especially useful when cutting hearttissue and the heart muscle is contracted during systole. Optionally,the device 120 can augment the process by pacing of tissue usingelectrical impulses. The shaft of the device can also be shaped tofacilitate placement of the device against various places within theheart.

FIG. 2A illustrates perspective partial cross sectional view of a farend 114 of the device 100 of FIGS. 1A and 1B. In this example, the farend 114 of the flexible shaft includes a relatively rigid section 122coupled to the shaft 110. The rigid section 122 carries a cutting member140 that is secured to the rigid section 122 using a pivot member 144.The cutting member 140 depicted is for illustration purposes only. Anynumber of blade shapes can be employed in addition or in combinationwith the illustrated cutting member. The cutting member 140 is alsocoupled to a link member 148 at a connection point 150. The link member148 extends through the shaft 110 and is secured to the actuating member106 discussed above. The link 148, a wire in the illustrated example,can include additional components to assist in applying a tensile forceto the cutting member 140. In the illustrated example, the link member148 includes an inner tube 152 and an outer tube 154 that are locatedwithin a passage 118 of the flexible shaft 110. Such components canimprove the structural integrity of the link 148 or can serve toinsulate and/or separate the link 148 from electrical components (notillustrated) extending through the passage 118. The passage can alsoinclude a valve either in the shaft and/or in the handle continuous toprevent back bleeding into the catheter. A channel for a guide wire canalso be used.

FIG. 2B illustrates a partial side view of the device 100 discussedabove, as shown the link 148 is secured to the actuating member 106(shown in FIGS. 1A and 1B) such that upon application of a tensileforce, the link member 148 causes movement of the cutting member 140.However, prior to actuation, the cutting member 140 is retained withinthe device 100 so that the cutting surface 14 is shielded and cannotinadvertently cut tissue. Variations of the device can also includeadditional features 160 can be coupled to the cutting member 140 and/orthe link 148 such as a strain gauge, spring, or similar structures thatallow either retention of the cutting member within the device 100 ormonitoring of the cutting member 140 as it cuts tissue. As illustrated,a variation of the device 100 includes a cutting member 140 having alink connection point 150 that is offset from an axis A-A of an area ofthe device 100 immediately surrounding the cutting member. Thiseccentric configuration improves actuation of the cutting member and cancause the far end of the device 100 to preferentially apply a forcetoward a lateral side of the device where the cutting edge 142 iseventually exposed. Such a feature can increase the ability and ease ofwhich the physician can push the cutting edge 142 into the heart muscle.In additional variations, the entire cutting assembly 140 (including thepivot point 144) is offset from the axis towards the lateral side of thedevice 100.

FIG. 2B also illustrates an optional sheath 164 or cover that can beslidably mounted on the flexible shaft 110. During advancement orpositioning of the device, the sheath 164 can be advanced over theopening 124 to prevent the cutting member 140 from inadvertentlydamaging tissue. Moreover, the sheath 164 can function as an addedsafety measure since distal movement (in the direction of arrows 166 canseparate the cutting member from tissue or can push the cutting memberback into the device 100 if the link 148 fails.

FIG. 2C illustrates a proximal or tensile force 162 applied to the link148 causing the cutting member 140 to pivot out of the opening 124towards a lateral side of the device 100. In the illustrated variation,the cutting edge 142 is exposed in a rearward direction so that pullingon the device 100 allows the cutting member 140 to cut tissue when thecutting member is advanced adjacent to or positioned within tissue. Asnoted above, the main passage 118 of the device (or any additional lumenor fluid supply tube) can be used to deliver any number of fluids orsubstances to an opening in the device, including but not limited to thecutting member opening 124.

In alternate variations, the cutting member 140 includes cutting edges142 on the front side or on both sides of the cutting member 140 toallow rearward and forward cutting. FIG. 2C also illustrates the link148 being eccentric in relation to an axis of the device. This featureresults in a lateral force component as noted by arrows 168. The lateralforce component 168 is directed towards the lateral side of the deviceand assists in maintaining the cutting member 140 within tissue duringcutting. As noted above the lateral force causes the catheter todifferentially bend or urges the far end of the device 100 toward theblade side (lateral side), increasing the ability to push the blade intothe heart muscle or other soft tissue. Additional variations of thedevice do not rely upon eccentric placement of the cutting member orlink but create a lateral force through adjustment of the bladeconfiguration. In addition, variations of the device include a pivot 144that is located distally to the link attachment point 146 when thecutting member 140 is exposed. As shown in FIG. 2C, the link attachmentpoint 146 is proximally located relative to the pivot 144. Thisconfiguration prevents interference between the link 148 and the pivot144 of the cutting member 140 and allows the link to apply lateral forceto the far end of the device so that the device flexes in the directionof the cutting member 140.

As noted above, a variation of the device 100 can include the cuttingmember 140 that is positioned within a rigid section 122 that isadjacent to the flexible shaft 110. The rigid section preventsdeflection of the area adjacent to the cutting member opening 124, whichallows for greater control of the amount of exposure of the cuttingedge.

FIG. 3A illustrates a variation of the device where the rigid section122 comprises an enclosure that is secured to a distal end of theflexible shaft 110. The enclosure 122 can comprise a conductive materialso that it can be used to apply energy, pace tissue, or sense forcontact with tissue. In such a case, the enclosure can be electricallycoupled to a power supply 130 via known means 136. Alternatively, theenclosure can comprise an insulated or non-conductive structure butstill selected to maintain rigidity as described above.

Alternatively, or in combination, the cutting member 140 can be selectedfrom a conductive material and electrically coupled to a power supply138 via known means. In additional variations, the cutting member 140can be fabricated from a non-conducting material or insulative material(e.g., ceramic, polymer, a composite material). In the latter case, thecutting member 140 can optionally include one or more electrodes orenergy transfer surfaces that are affixed or positioned on one or bothsides of the cutting member 140.

In an additional variation, as shown in FIG. 3B, the flexible shaft 110can house the cutting member 140. In such a case, a reinforcement member168 (either external or internal to the shaft 110) can be coupled to theflexible shaft 110 where the reinforcement member renders the area as arigid section.

FIG. 3B also illustrates a variation of the device where the flexibleshaft 110 includes one or more electrodes 170, 172 on an exterior of theshaft 110 and adjacent to the opening 124. As shown, the electrodes canbe coupled to a power supply using known means. The electrodeconfiguration can be employed on the enclosure shown in FIG. 3A as well.

FIG. 4A illustrates an example of a treatment device as described hereinbeing used in a chamber of the heart 9. Clearly, the device 100 can beused in any pocket or cavity of soft tissue. As illustrated, a physicianadvances a treatment device 100 into a chamber 8 of the heart 9. Onceinside the chamber 8, in this example the left ventricle, the physiciancan advance an atraumatic tip 120 of the device 100 against tissue (inthis case the apex of the chamber) to provide an opposing force to allowpenetration of the cutting member into cardiac tissue. Because theatraumatic tip 120 is elastic and resilient there is a reduced risk thatthe tip 120 will create undesired injury. In addition, the flexibleshaft of the device 100 can include any number of reinforcing member 126such as braids, coils, polymer coextrusion, etc., that maintainstorqueability and/or column strength of the flexible member. Suchcharacteristics are required for accurate placement of the cuttingelement against the desired area of tissue. As noted above, electrodes(or components of the device) can be used with a power supply 130 toassist in placement of the device, and/or provide therapeutic treatment.In some variations the device can be configured as a bi-polar device,with electrodes of opposite polarity on the device. Alternatively, thedevice can function in a monopolar or unipolar configuration. In such acase an external electrode 131 can be positioned on a remote area of thepatient's body.

FIG. 4B shows a magnified view of the device 100 being advanced intoposition at the apex of the heart where deformation of the atraumatictip 120 applies a force in a lateral direction 168. As noted above, theatraumatic tip 120 is not limited to a curved configuration; instead,any shape that delivers a biasing force can be employed. Furthermore,some variations of the device may not require a biasing force applied bythe tip.

FIG. 4B also illustrates advancement of the cutting member 140 to thelateral side. As noted above, this action can also apply a lateral forceto assist in placement of the cutting element 140 within tissue. Asshown in FIG. 4C, The lateral force can assist retention of the cuttingelement 140 as it is withdrawn in a proximal or rearward directionleaving the therapeutic cut 4 in tissue. As noted above, a strain gaugeor other structure can be used to measure the drag or resistance on thedevice to assist in determining whether the cutting element is engagedin tissue. In any case, as noted above, tension applied by the link notonly actuates the cutting member, but also, when positioned in aneccentric location within the shaft, the tension also causes thecatheter to differentially bend toward the blade side, increasing theability to push the blade into the heart muscle.

Again, the shape of the blade or cutting member can be selected so thatit stays in tissue while being pulled. In certain variations, thecutting member opens from distal to proximal direction so that it can besafely closed by retracting into the device sheath or by pushing asheath over the cutting member.

The cutting element can be an electrically insulated blade (e.g., madeof ceramic, polymers, or a composite structure) that allows electrodeson both sides of blade to be electrically isolated from each other.Electrodes can be used to monitor EKG for a current of injury todemonstrate cutting, can be used to pace the heart, demonstrating thatthe blade is within the heart muscle, and for other uses(electrocautery, depth measurement, electrodeposition ofdrugs/chemicals). If the cutting element is fabricated from a conductivematerial, it can be used for pacing, which allows a cut to be madeduring systole and pushes muscle onto blade for cutting. Alternatively,or in combination, the rigid section of the device can be used as areturn electrode for sensing, treatment or manipulation of tissue asdiscussed above.

FIGS. 5A-5C illustrate additional variations of devices and methods forperforming the treatment as described herein. Such variations can becombined with the variations discussed above and/or can serve asstand-alone features/devices where applicable. For example, FIG. 5Aillustrates a variation of a device where articulation of the shaft isdecoupled from actuation of the cutting member 142. Articulation of theshaft can be performed by either pushing or pulling of the member 174.Alternatively, the member can comprise any number of pre-shaped styletsthat allow a physician to select the degree of curvature desired inorder to perform an incision.

FIG. 5B shows another variation of a device where the shaft applies alateral force 168 through the use of one or more sheaths 176. Thesheaths can include pre-shaped sheaths having an angle A or a set ofpre-shaped sheaths having a range of angles so that the physician canselect the degree of deflection or amount of lateral force 168 desired.

FIG. 5C shows another variation of a device. In this example, the deviceincludes a servo or other deflection motor that drives a lead screw 178where the lead screw 178 engages a second threaded member 180 fixed tothe shaft where relative rotation 182 causes movement of the lead screwrelative to the threaded member 180 to create the lateral force 168. Thedeflection motor can also actuate the blade or can be independent of theblade.

It should be understood that application of the lateral force 168 can beobtained through any number of means used for control of devices and/orcontrol of medical devices. For example, the device and/or cuttingmember can be controlled using a robotic system such as those providedby Intuitive Surgical, Hansen Medical, etc. Alternatively, the devicecan employ a memory element that produces deflection upon the elementreaching a certain condition (e.g., body temperature), or upon theapplication of a current to the element.

As noted above, the depth of cut can be varied by making the bladelonger or shorter using the adjustments and stops discussed above. Itcan also be varied in a given-length blade catheter by exposing more orless blade with the angle of exposure varying from barely out of thecatheter to 90 degrees from the long axis of the catheter.

The handle shown in FIGS. 1A and 1B can be ergonomic and allow thecutting element to be exposed by flexing the fingers of the operator'shand, and retracted by extending the fingers. The stop, as discussedabove, can be placed on the handle so that the maximum blade exposurecan be limited to a preset angle, corresponding to a preset depth.Electrical components can be connected at the handle which iselectrically connected to the blade through the pull wire.

In many variations, the tip or cutting edge of the cutting member issharp enough to allow the heart muscle (or other soft tissue) to bestabbed and the angle between the dull and sharpened side is acuteenough to allow cutting with minimal force. An alternative sickle-shapeis also possible, which causes the blade to remain within the tissuewhile being pulled but requires the knife to be pushed backward afterthe cut to disengage the tissue.

The device can also employ a pull-apart or splittable cover that retainsthe curved atraumatic tip temporarily straight to allow for easy entryinto a guiding sheath during use. When this pull-apart cover is pulledoff, the curled tip bends once it is unconstrained by the guidingsheath. This makes for ease of use, but also ensures single-use.

The diameter of the catheter does not constrain the length of blade ordepth of cut as the width of the blade can be reduced to fit within evena small catheter. The length of the blade can therefore be several timesthe diameter of the catheter. For example, in one example the diameterof the device was 7 French, allowing it to go through the smallest ofguide catheters known.

The methods described herein can be performed using a number ofadditional modes to determine proper placement. For example, the methodscan be performed under fluoroscopy and/or with contrast agents.Alternatively, or in combination, a device can include a pressuresensing tip or along catheter at one or multiple points that determinewhen the device is positioned against the heart wall. In anothervariation, the device can include an opening at the distal end that isattached to arterial sensing equipment. Next, the waveform of a pressurewave is observed. When the hole is covered by tissue, the tissue bluntsthe waveform. This effect can be used as a test for catheter wallapposition. A physician can also confirm placement using anechocardiogram (TTE, TEE, intracardiac) where image shows position ofdevice relative to wall/tissue.

Current can also be used to determine blade contact with tissue. Forexample, a current can be placed through the tissue (through ekg orsimilar type electrochemical sensing). As the blade touches the tissue,a voltage change can be measured from the circuit completed by theblade's contact with tissue.

Additionally, implantable hardware within, near, or around thesecuts/holes with drug eluting capability may be part of this procedure.As well, the hardware (knife or otherwise) used to make the interventionon the cardiac chambers may be coated with drugs much like in drugcoated balloon angioplasty.

As noted herein, the physician can create one or more therapeuticincisions, cuts, cores, holes, or other similar therapeutic damage toincrease volume in the ventricle when in diastole. As noted above, thisdamage reduces the stiffness of the ventricle (or cardiac muscle in thewall) to improve ventricular filling and reduce diastolic fillingpressure (which resists blood flow into the ventricle). The methodincludes making one or more therapeutic damage sites within one or morechambers of the heart. In this variation, the treatments occur in theendocardium 2. Any of the treatment devices 3 described herein caninclude spring biasing, steering, a steerable sheath or catheter, a pullwire, or other mechanism to assist in navigation or apposition of theworking end 4 of the device 3 against the target site.

Devices for use in the methods described herein can incorporatealternative design options to improve safety to critical structures andto ensure cuts are made as expected (any combination or singular use ofthe below may be incorporated with any of the variations of the methodsor devices discussed herein.)

The devices described herein can be used in other applications as well.For example, devices have application to make MAZE incisions by makingmultiple cuts in or around the pulmonary vein/s to interrupt conductionof atrial electrical activity. The devices and procedures can be usedfor commisurotomy, by cutting valve in various places includingcommissures to decrease valvular stenosis. The devices can be used forany and all cardiovascular structures that have undergonestenosis/sclerosis, such as renal arteries/pulmonary veins after RFexposure by cutting longitudinally with knife catheter. Furthermore, thedevices can be used to perform plastys in all chambers of the heart bycutting longitudinally with the knife blade. Another potential useincludes septal ablations by cutting longitudinally with the knifedevice; endarterectomy using the blade as cutting device to removeplaque. This peeling/cutting device will be proximal to a distalumbrella unit at the tip of the device that is used to both peel plaqueand prevent embolization. Current open methods of carotid endarterectomylead to stenosis secondary to opening the vessel and subsequentlyclosing the incision; our method would provide an advantage over this aswe would not be opening the vessel. Glaucomaplasty via Canal of Schlemincision thus increasing the diameter of the canal, increasing the flowof aqueous humor, and thus decreasing intraocular pressures. The devicescan be used for tear duct plasty as well as looking for chronicsinusitis; third ventriculoplasty for obstructive hydrocephalus; andpsialalithiasis intervention to remove stones.

We claim:
 1. A medical device for creating elongated incisions withinsoft tissue, the device comprising: a handle comprising a handle bodyand an actuating member; a flexible shaft having a near end coupled tothe handle body and a far end, the flexible shaft; an atraumatic tiplocated at the far end; a cutting member pivotally secured within theflexible shaft and having a cutting edge; and a linking member couplingthe actuating member of the handle to the cutting member,